Hey mama I used to fortify my babies breastmilk with coconut oil. I would put in a certain amount per oz (can't remember now) and she loved it. She did not like formula, and I did not want to throw away BM because it sat out too long with formula in it. Formula can also contribute to the constipation. I'm still trying to pack pounds on my girl. She's tiny and eats like a bird. It's so stressful. Good luck!